The present disclosure relates to electric and electronic apparatuses, circuits, and communication systems.
In recent years, due to the miniaturization of MOS transistors (Metal Oxide Semiconductor Field Effect Transistors), variation of the MOS transistor characteristics has been increased, and with their power supply voltages getting lower, the operation margins have been smaller. It therefore has become difficult to achieve optimal circuit characteristics with relatively small area and low power consumption, especially in analog circuits.
Accordingly, there has been suggested a technique in which characteristic adjustment is performed immediately after the power is turned on, thereby optimizing circuit characteristics; and then operating the circuit; in order to address the problem of the variation of the circuit characteristics and achieve optimal circuit characteristics with relatively small area and low power consumption (see, for example, Japanese Patent Application Laid-open No. 2009-124737).